Abstract

We analyse here a wide sample of carbonaceous chondrites from historic falls (e.g. Allende,
Cold Bokkeveld, Kainsaz, Leoville, Murchison, Murray, Orgueil and Tagish Lake) and from
NASA Antarctic collection.With the analysis of these meteorites we want to get new clues on
the role of aqueous alteration in promoting the reflectance spectra diversity evidenced in the
most primitive chondrite groups. The selected meteorite specimens are a sample large enough
to exemplify how laboratory reflectance spectra of rare groups of carbonaceous chondrites
exhibit distinctive features that can be used to remotely characterize the spectra of primitive
asteroids. Our spectra cover the full electromagnetic spectrum from 0.2 to 25 μm by using
two spectrometers. First one is an ultraviolet (UV)–near-infrared (NIR) spectrometer that
covers the 0.2–2 μm window, while the second one is an attenuated total reflectance infrared
spectrometer covering the 2–25 μm window. In particular, laboratory analyses in the UV–NIR
window allow obtaining absolute reflectance by using standardized measurement procedures.
We obtained reflectance spectra of specimens belonging to the CI, CM, CV, CR, CO, CK,
CH, R and CB groups of carbonaceous chondrites plus some ungrouped ones, and it allows
identifying characteristic features and bands for each class, plus getting clues on the influence
of parent body aqueous alteration. These laboratory spectra can be compared with the remote
spectra of asteroids, but the effects of terrestrial alteration forming (oxy)hydroxides need to
be considered.